4,4′-(Propane-2,2-diyl)diphenol, more commonly known as bisphenol-A (BPA), is a widely used monomer for the production of polymers including epoxy resins, polyurethanes, polyacrylates and polycarbonates. The aromatic moieties of BPA are highly rigid, leading to polymers with great mechanical strength and high glass transition temperatures.
As a result, BPA-based polymers and resins are found in a wide range of products and applications, from consumer products to medical devices. For example, BPA-based epoxy resins are used for coil and can coatings for food and beverage containers; BPA-based polycarbonates and their copolymers are used to produce food containers including baby bottles, tableware, water bottles; and BPA-based polymers are used in medical devices including storage devices, renal dialysis devices, cardiac surgery products, surgical instruments, and intravenous connection components. Such widespread use has made BPA among the highest production volume industrial chemicals, leading to a substantial production infrastructure for the compound.
In recent years, health concerns have arisen regarding BPA-based polymers. Such polymers are susceptible to degradation and yellowing upon exposure to light, heat and certain chemicals. Upon degradation of the polymers, BPA and its derivatives can make its way into the contents of the food and beverage containers or medical storage devices and, subsequently, into the body. For example, BPA-containing polycarbonates have been shown to hydrolyze and release BPA monomers (see (a) Mercea, P., J. Applied Polymer Science (2009), 112(2), 579; (b) Kang, Jeong-Hun; Kondo, Fusao, Food Additives & Contaminants (2002), 19(9), 886; (c) Howe, Susan R.; Borodinsky, Lester, Food Additives and Contaminants (1998), 15(3), 370; and (d) Mountfort, Katrina A.; Kelly, Janet; Jickells, Sue M.; Castle, Laurence, Food Additives and Contaminants (1997), 14(6-7), 737). BPA is considered to be an endocrine disruptor and has been suggested to cause or contribute to birth defects, miscarriages, neurological problems, menstrual cycle disruptions, testicular disruption, and breast growth in males among other effects (see (a) Vandenberg, L. N. Repro. Toxicol. (2007) 24, 139; (b) Welshon, W. V., Nagel, S. C., vom Saal, F. S. Endocrinology (2006) 147(6), s56; and (c) vom Saal, F. Endocrinology (2006) 147(8), 3679). In view of these concerns, various government authorities around the world have become more restrictive in regulating the amounts of BPA in certain products, and bans on the use of BPA in certain products such as baby bottles, have been instituted in some countries.